To add 2GB of SWAP memory on this droplet:
dd if=/dev/zero of=/swap bs=1024 count=2097152 mkswap /swap && chown root. /swap && chmod 0600 /swap && swapon /swap echo /swap swap swap defaults 0 0 >> /etc/fstab echo vm.swappiness = 0 >> /etc/sysctl.conf && sysctl -p
apt-get install -y nagios3 nagios-nrpe-plugin usermod -a -G nagios www-data chmod -R g+x /var/lib/nagios3/ sed -i 's/check_external_commands=0/check_external_commands=1/g' /etc/nagios3/nagios.cfg
You will be prompted for MySQL root password, we chose "PassWord", you should change it to something stronger.
Set Nagios Admin Panel Password:
htpasswd -c /etc/nagios3/htpasswd.users nagiosadmin service nagios3 restart && service apache2 restart
Make sure to keep this username as "nagiosadmin" - otherwise you would have to change /etc/nagios3/cgi.cfg and redefine authorized admin.
Now you can navigate over to your droplet's Nagios panel at http://IP/nagios3 (http://198.211.117.129/nagios3/ for our example):
You will be prompted to enter your password, which you've specified in Step 3.
As you can see, we don't have any hosts currently being monitored, so lets set that up next.
Now we should add our hosts that will be monitored by Nagios. For example, we will setup monitoring for cloudads.tk (198.211.117.101), which runs Ubuntu 12.10 as well.
From public ports, we can monitor ping, any open ports such as webserver, e-mail server, etc.
For internal services that are listening on localhost, such as MySQL, memcached, system services, we will need to use NRPE.
apt-get install -y nagios-plugins nagios-nrpe-server
This next step is where you get to specify any manual commands that Monitoring server can send via NRPE to these client hosts.
Make sure to change allowed_hosts to your own values.
Edit /etc/nagios/nrpe.cfg
log_facility=daemon pid_file=/var/run/nagios/nrpe.pid server_port=5666 nrpe_user=nagios nrpe_group=nagios allowed_hosts=198.211.117.129 dont_blame_nrpe=1 debug=0 command_timeout=60 connection_timeout=300 include=/etc/nagios/nrpe_local.cfg include_dir=/etc/nagios/nrpe.d/ command[check_users]=/usr/lib/nagios/plugins/check_users -w 5 -c 10 command[check_load]=/usr/lib/nagios/plugins/check_load -w 15,10,5 -c 30,25,20 command[check_hda1]=/usr/lib/nagios/plugins/check_disk -w 20% -c 10% -p /dev/vda command[check_zombie_procs]=/usr/lib/nagios/plugins/check_procs -w 5 -c 10 -s Z command[check_total_procs]=/usr/lib/nagios/plugins/check_procs -w 150 -c 200
Note:
In check_disk above, the partition being checked is /dev/vda - make sure your droplet has the same partition by running df -h /
You can also modify when to trigger warnings or critical alerts - above configuration sets Warning at 20% free disk space remaining, and Critical alert at 10% free space remaining.
We should also setup firewall rules to allow connections from our Monitoring server to those clients and drop everyone else:
iptables -N NRPE iptables -I INPUT -s 0/0 -p tcp --dport 5666 -j NRPE iptables -I NRPE -s 198.211.117.129 -j ACCEPT iptables -A NRPE -s 0/0 -j DROP /sbin/iptables-save
Now you can start NRPE on your client host:
service nagios-nrpe-server restart
Back on our Monitoring server, we will have to create config files for each of our client servers:
All configs can be stored in /etc/nagios3/conf.d in individual .cfg files (for example: /etc/nagios3/conf.d/cloudads.tk.cfg)
Edit /etc/nagios3/conf.d/cloudads.tk.cfg and add the following lines:
define host { use generic-host host_name cloudads.tk alias cloudads.tk address 198.211.117.101 } define service { use generic-service host_name cloudads.tk service_description PING check_command check_ping!100.0,20%!500.0,60% } define service { use generic-service host_name cloudads.tk service_description SSH check_command check_ssh notifications_enabled 0 } define service { use generic-service host_name cloudads.tk service_description Current Load check_command check_load!5.0!4.0!3.0!10.0!6.0!4.0 }
After you are done editing your config files, make sure to restart Nagios for changes to take effect:
service nagios3 restart
You can add more services to be monitored as desired, and even create your own Nagios plugins.
Navigate over to your Monitoring Server's IP address http://IP/nagios3 and enter password set in Step 2.
Now you should be able to see all the hosts and services.
And you are all done!
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Do you have any idea how to install nagios nrpe plugins without being forced to install Apache2? I don’t need Apache because Nginx is being used.
i followed everything but when i login and click on a menu on the sidebar i get The requested URL /cgi-bin/nagios3/status.cgi was not found on this server.
can someone help pls
Whoa, liking the updated look of the guide!
Has anyone changed the email option to <our own email address> as apposed to /var/lib/root ? if so, can anybody help me in setting up nagios for emailing our own email address
@hykavitha: Take a look at <a href=“http://www.geekpeek.net/nagios-configuration/”>http://www.geekpeek.net/nagios-configuration/</a>
Hi Kamal,
I followed all the steps, I understand that we did install nagios3 and I can go to http://IP/nagios3 . I want to monitor my websites how do I set up the websites & where?
Thanks, I’ve updated the article. :]
Step 6 should have http://IP/nagios3 as opposed to http://IP/nagios
Anyone knows how much resources does nagios consume? I have the 2 core, 2GB of RAM box.
@mahaveer_lohia_1990: What do you mean?